Is CRISPR/Cas9-based multi-trait enhancement of wheat forthcoming?

Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) technologies have been implemented in recent years in the genome editing of eukaryotes, including plants. The original system of knocking out a single gene by causing a double-strand break (DSB), followed by non-homologous end joining (NHEJ) or Homology-directed repair (HDR) has undergone many adaptations. These adaptations include employing CRISPR/Cas9 to upregulate gene expression or to cause specific small changes to the DNA sequence of the gene-of-interest. In plants, multiplexing, i.e., inducing multiple changes by CRISPR/Cas9, is extremely relevant due to the redundancy of many plant genes, and the time- and labor-consuming generation of stable transgenic plant lines via crossing. Here we discuss relevant examples of various traits, such as yield, biofortification, gluten content, abiotic stress tolerance, and biotic stress resistance, which have been successfully manipulated using CRISPR/Cas9 in plants. While existing studies have primarily focused on proving the impact of CRISPR/Cas9 on a single trait, there is a growing interest among researchers in creating a multi-stress tolerant wheat cultivar 'super wheat', to commercially and sustainably enhance wheat yields under climate change. Due to the complexity of the technical difficulties in generating multi-target CRISPR/Cas9 lines and of the interactions between stress responses, we propose enhancing already commercial local landraces with higher yield traits along with stress tolerances specific to the respective localities, instead of generating a general 'super wheat'. We hope this will serve as the sustainable solution to commercially enhancing crop yields under both stable and challenging environmental conditions.

Tuberculosis retreatment outcomes and associated factors: a mixed-methods study from Puducherry, India.

Setting: Four Tuberculosis (TB) Units in the Union Territory of Puducherry in India. Objectives: To identify factors associated with unfavourable outcomes among retreatment TB cases in Puducherry. Design: The study had a mixed-methods design in which routinely reported TB data from retreatment TB cases registered during 2014 and 2015 were used for the quantitative part; the qualitative phase comprised interviews and focus group discussions with health care providers. Results: Among the 392 retreatment cases, 297 (75.8%) had favourable outcomes. Outcome for previous treatment such as loss to follow-up (LTFU) (adjusted relative risk [aRR] 1.6, 95%CI 1.1-2.4, P = 0.001), treatment failure (aRR 1.7, 95%CI 1.04-2.8, P = 0.03) and pre-treatment weight <40 kg (aRR 1.8, 95%CI 1.3-2.5, P = 0.001) had increased risk for unfavourable outcomes. Health care providers reported that alcoholism, lack of family support, job-related issues and lack of access to trained staff for injections were some of the reasons for unfavourable outcomes. Providing incentives, nutritional supplements and early retrieval of the LTFU cases were some of the suggestions to reduce unfavourable outcomes. Conclusion: Outcome of previous treatment and low pre-treatment weight of the patient affected retreatment outcomes. Health professionals and workers highlighted social and health system-related factors. Commitment at all levels on the part of health care providers and addressing their concerns can improve retreatment outcomes.

Contexte : Quatre unités tuberculose (TB) dans le territoire de Puducherry en Inde.Objectif : Identifier les facteurs associés à des résultats défavorables parmi les cas de retraitement de TB à Puducherry.Schéma : Schéma à méthodes mixtes dans lequel les données TB recueillies en routine relatives aux cas de retraitement de TB enregistrés en 2014 et 2015 ont été utilisés de manière quantitative. L'aspect qualitatif a été basé sur des entretiens et des discussions en groupe focal avec les prestataires de soins de santé.Résultats : Parmi les 392 cas de retraitement, 297 (75,8%) ont eu un résultat défavorable. Les résultats du traitement précédent comme les pertes de vue (LTFU) (risque relative ajusté [RRa] 1,6 ; IC95% 1,1­2,4 ; P = 0,001), un échec du traitement (RRa 1,7 ; IC95% 1,04­2,8 ; P = 0,03) et un poids avant traitement <40 kg (RRa 1,8 ; IC95% 1,3­2,5 ; P = 0,001) ont majoré le risque de nouveau résultat défavorable. Les prestataires de soins de santé ont rapporté que l'alcoolisme, l'absence de soutien familial, des problèmes professionnels et l'absence d'accès à du personnel formé pour les injections ont été parmi les causes de résultats défavorables. On a suggéré de réduire ces problèmes, notamment en fournissant des incitations et des suppléments nutritionnels et en recherchant rapidement les LTFU.Conclusion : Les résultats du traitement précédent et un faible poids avant le traitement ont affecté les résultats du retraitement. Le personnel de santé a attribué ce fait à des facteurs sociaux et liés au système de santé. L'engagement à tous les niveaux des prestataires de soins de santé et le fait de répondre à leurs préoccupations peuvent améliorer les résultats du retraitement.

Marco de Referencia: Cuatro unidades de tuberculosis (TB) en Puducherry, que es un Territorio de la Unión en la India.Objetivos: Reconocer los factores que se asocian con los desenlaces desfavorables en los casos de retratamiento de la TB en Puducherry.Método: Fue este un estudio con diseño de método mixtos; en el análisis cuantitativo se utilizaron los datos corrientes de notificación de los casos de retratamiento de la TB registrados en el 2014 y el 2015 y en la fase cualitativa se realizaron entrevistas y sesiones en grupos de opinión con los proveedores de atención de salud.Resultados: De los 392 casos en retratamiento, 297 (75,8%) alcanzaron desenlaces favorables. Se observó que el riesgo aumentado de desenlaces desfavorables se asociaba con el desenlace del tratamiento anterior como la pérdida durante el seguimiento (LTFU) (riesgo relativo ajustado [RRa] 1,6; 95%CI 1,1­2,4; P = 0,001), el fracaso terapéutico (RRa 1,7; 95%CI 1,04­2,8; P = 0,03) y con un peso <40 kg antes de iniciar el tratamiento (RRa 1,8; 95%CI 1,3­2,5; P = 0,001). Los profesionales de salud refirieron el alcoholismo, la falta de apoyo familiar, los problemas relacionados con el trabajo y la falta de acceso a personal capacitado para las inyecciones como algunas de las razones de los desenlaces desfavorables y sugirieron la provisión de incentivos, los suplementos nutricionales y la recuperación rápida de los casos LTFU como estrategias para corregirlos.Conclusión: El desenlace de un tratamiento anterior y el bajo peso del paciente antes de iniciar el tratamiento afectan el desenlace de los casos de retratamiento de la TB. Los profesionales y los trabajadores de salud atribuyeron estos resultados a factores sociales y factores relacionados con el sistema de salud. La participación de los proveedores de atención de salud a todos los niveles y la respuesta a sus inquietudes contribuirán a mejorar los desenlaces del retratamiento de la TB.

Identification of defense-related genes newly-associated with tomato flower abscission.

The current abscission model suggests the formation of a post-abscission trans-differentiation of a protective layer as the last step of the process. The present report expands the repertoire of genes activated in the tomato flower abscission zone (AZ), which are likely to be involved in defense responses. We identified four different defense-related genes, including: Cysteine-type endopeptidase, α-Dioxygenase 1 (α-DOX1), HopW-1-1-Interacting protein2 (WIN2), and Stomatal-derived factor-2 (SDF2), that are newly-associated with the late stage of the abscission process. The late expression of these genes, induced at 8-14 h after flower removal when pedicel abscission was already in progress, was AZ-specific, and was inhibited by treatments that prevented pedicel abscission, including 1-methylcyclopropene pretreatment or IAA application. This information supports the activation of different defense responses and strategies at the late abscission stages, which may enable efficient protection of the exposed tissue toward different environmental stresses.

Microarray analysis of the abscission-related transcriptome in the tomato flower abscission zone in response to auxin depletion.

The abscission process is initiated by changes in the auxin gradient across the abscission zone (AZ) and is triggered by ethylene. Although changes in gene expression have been correlated with the ethylene-mediated execution of abscission, there is almost no information on the molecular and biochemical basis of the increased AZ sensitivity to ethylene. We examined transcriptome changes in the tomato (Solanum lycopersicum 'Shiran 1335') flower AZ during the rapid acquisition of ethylene sensitivity following flower removal, which depletes the AZ from auxin, with or without preexposure to 1-methylcyclopropene or application of indole-3-acetic acid after flower removal. Microarray analysis using the Affymetrix Tomato GeneChip revealed changes in expression, occurring prior to and during pedicel abscission, of many genes with possible regulatory functions. They included a range of auxin- and ethylene-related transcription factors, other transcription factors and regulatory genes that are transiently induced early, 2 h after flower removal, and a set of novel AZ-specific genes. All gene expressions initiated by flower removal and leading to pedicel abscission were inhibited by indole-3-acetic acid application, while 1-methylcyclopropene pretreatment inhibited only the ethylene-induced expressions, including those induced by wound-associated ethylene signals. These results confirm our hypothesis that acquisition of ethylene sensitivity in the AZ is associated with altered expression of auxin-regulated genes resulting from auxin depletion. Our results shed light on the regulatory control of abscission at the molecular level and further expand our knowledge of auxin-ethylene cross talk during the initial controlling stages of the process.